Method and System for Implementing an Analytical Wirelength Formulation for Unavailability of Routing Directions

1. A method of estimating an interconnect line length to connect circuit elements of a net in an integrated circuit (“IC”) layout, the net representing interconnections between a set of circuit elements in the IC layout, the method comprising: (a) identifying a plurality of circuit elements for the net; (b) identifying the availability of routing directions to route the plurality of circuit elements; (c) compensating a bounding box to take into account one or more unavailable routing directions, the bounding box encompassing the plurality of circuit elements of the net, in which the bounding box is determined using a formulation that is continuous along with its derivative; and (d) using the bounding box to estimate the interconnect line length to connect the circuit elements of the net.

2. The method of claim 1 in which the bounding box is compensated using a continuous formulation.

3. The method of claim 1 in which the bounding box is compensated using a non-continuous formulation.

4. The method of claim 1 in which a side of the bounding box is not compensated.

5. The method of claim 4 in which compensation of the side of the bounding box is not performed if the length of the side is not significant enough or is beneath a defined threshold.

8. A method of estimating an interconnect line length to connect circuit elements of a net in an integrated circuit (“IC”) layout, the net representing interconnections between a set of circuit elements in the IC layout, the method comprising: (a) identifying a plurality of circuit elements for the net; (b) identifying the availability of routing directions to route the plurality of circuit elements; (c) compensating a bounding box to take into account one or more unavailable routing directions, the bounding box encompassing the plurality of circuit elements of the net, in which the compensated bounding box comprises a rotated bounding box that is rotated by an angle other than 0, 90, 180, 270, or 360 degrees, and (d) using the bounding box to estimate the interconnect line length to connect the circuit elements of the net.

9. A computer program product comprising a computer usable medium having executable code to execute a method for estimating an interconnect line length to connect circuit elements of a net in an integrated circuit (“IC”) layout, the net representing interconnections between a set of circuit elements in the IC layout, the method comprising: (a) identifying a plurality of circuit elements for the net; (b) identifying the availability of routing directions to route the plurality of circuit elements; (c) compensating a bounding box to take into account one or more unavailable routing directions, the bounding box encompassing the plurality of circuit elements of the net, in which the bounding box is determined using a formulation that is continuous along with its derivative; and (d) using the bounding box to estimate the interconnect line length to connect the circuit elements of the net.

12. A computer program product comprising a computer usable medium having executable code to execute a method for estimating an interconnect line length to connect circuit elements of a net in an integrated circuit (“IC”) layout, the net representing interconnections between a set of circuit elements in the IC layout, the method comprising: (a) identifying a plurality of circuit elements for the net; (b) identifying the availability of routing directions to route the plurality of circuit elements; (c) compensating a bounding box to take into account one or more unavailable routing directions, the bounding box encompassing the plurality of circuit elements of the net, in which a side of the bounding box is not compensated and, in which compensation of the side of the bounding box is not performed if the length of the side is not significant enough or is beneath a defined threshold; and (d) using the bounding box to estimate the interconnect line length to connect the circuit elements of the net.

13. A computer program product comprising a computer usable medium having executable code to execute a method for estimating an interconnect line length to connect circuit elements of a net in an integrated circuit (“IC”) layout, the net representing interconnections between a set of circuit elements in the IC layout, the method comprising: (a) identifying a plurality of circuit elements for the net; (b) identifying the availability of routing directions to route the plurality of circuit elements; (c) compensating a bounding box to take into account one or more unavailable routing directions, the bounding box encompassing the plurality of circuit elements of the net, in which the compensated bounding box comprises a rotated bounding box that is rotated by an angle other than 0, 90, 180, 270, or 360 degrees; and (d) using the bounding box to estimate the interconnect line length to connect the circuit elements of the net.

14. A system for estimating an interconnect line length to connect circuit elements of a net in an integrated circuit (“IC”) layout, the net representing interconnections between a set of circuit elements in the IC layout, the method comprising: (a) logic for identifying a plurality of circuit elements for the net; (b) logic for identifying the availability of routing directions to route the plurality of circuit elements; (c) logic for compensating a bounding box to take into account one or more unavailable routing directions, the bounding box encompassing the plurality of circuit elements of the net, in which the bounding box is determined using a formulation that is continuous along with its derivative; and (d) logic for using the bounding box to estimate the interconnect line length to connect the circuit elements of the net.

17. A system for estimating an interconnect line length to connect circuit elements of a net in an integrated circuit (“IC”) layout, the net representing interconnections between a set of circuit elements in the IC layout, the method comprising: (a) logic for identifying a plurality of circuit elements for the net; (b) logic for identifying the availability of routing directions to route the plurality of circuit elements; (c) logic for compensating a bounding box to take into account one or more unavailable routing directions, the bounding box encompassing the plurality of circuit elements of the net, in which compensation of the side of the bounding box is not performed if the length of the side is not significant enough or is beneath a defined threshold; and (d) logic for using the bounding box to estimate the interconnect line length to connect the circuit elements of the net.

18. A method of estimating an interconnect line length to connect circuit elements of a net in an integrated circuit (“IC”) layout, the net representing interconnections between a set of circuit elements in the IC layout, the method comprising: (a) identifying a plurality of circuit elements for the net; (b) identifying the availability of routing directions to route the plurality of circuit elements; (c) compensating a bounding box to take into account one or more unavailable routing directions, wherein a side of the bounding box is not compensated, and compensation of the side of the bounding box is not performed if the length of the side is not significant enough or is beneath a defined threshold, the bounding box encompassing the plurality of circuit elements of the net; and (d) using the bounding box to estimate the interconnect line length to connect the circuit elements of the net.